Advanced countries such as USA, Japan and the like or other countries make a lot of efforts for the sake of safe driving of vehicles making use of various kinds of speed meters using microwaves or laser beams, i.e., radar, and safety alert transmitters for informing various situations of a road.
Particularly, although speed meters and signal detectors are currently used for traffic enforcement purpose in some countries, the speed meters and the signal detectors are permitted to be used as legal devices for helping safe driving in USA, Japan and the like, and use of the speed meters and the signal detectors tends to be legalized across the world.
With regard to the radar detector inducing safe driving of vehicles by detecting various signals as described above, various studies and patent applications are under progress even in Korea as is exemplified in the documents of the prior art as described below.
The documents of the prior art exemplified below are related to techniques for adding convenience to radar and/or a radar detector using a laser and also disclose basic techniques of the radar and the radar detector for detecting laser beams.
The radar detectors have been ceaselessly developed to detect various kinds of speed meters and inform a driver of road situations. However, previous studies are mainly focused on detecting speed meters and extending sensing distance.
A radio frequency band of radar applied to the speed meters is an X band (10.525 GHz±25 MHz), a K band (24.15 GHz±100 MHz) or a KA band (34.7 GHz±1,300 MHz), and in the case of a laser, a laser wavelength of 904 nm having a bandwidth of 33 MHz is applied.
As is well-known how dangerous it is to handle a navigator or a cellular phone while driving, in the case a radar detector, a driver's behavior of lowering audio sound or operating various functions using a button unit 600 while driving may act as a factor inviting a great danger to safe driving of the driver according to road conditions and driving situations. Particularly, latest vehicles have a serious problem in safety such that since the distance between the driver's seat and a device (the radar detector) placed on the dashboard or the windshield glass is long, movement of a driver for handling the radar detector increases, and keeping eyes ahead is neglected or even the movement can be applied to the steering wheel in the process of applying a handling force.
In the prior art, measures required for safety of a user when a driver should operate a radar detector while driving a vehicle are insufficient. When the radar detector senses a speed sensor or aurally informs the driver of road conditions or states, if the aural signal is too loud or lasts for an extended period of time, it may act as a factor hindering the driving.
In the prior art, a general radar detector is provided with separate buttons for decreasing the volume or performing a mute function so that a driver may not be hindered. Therefore, the driver decreases the volume or turns on the mute function by handling a corresponding button while driving.
Like this, an operation of handling (driving) the radar detector by a driver acts as a factor hindering safe driving of the driver. Although there are cases when an auto-mute function is applied for the convenience of drivers, it is insufficient to satisfy the requests and characteristics of various drivers since the auto-mute function is a convenience function executed only when a predetermined time is elapsed.
In addition, if the inner space of a vehicle is large or the vehicle is a large vehicle, the radar detector is placed at a place hard to operate by the driver or installed at a hidden place in many cases. Even in this case, the problem of threatening safety of a vehicle may occur due to unnatural handling of a button by the driver.
In addition, a conventional radar detector has a problem in that it cannot distinguish a normal signal (e.g., an electromagnetic signal or the like of a speed meter or a safety alert transmitter) from undesired signals in an environment interfered by the undesired signals, such as an area of severe radio interference, a downtown area where various signals are generated or the like, and malfunctions of the radar detector frequently occur due to the interference of the signals.